1. Field of the Invention
The present invention relates to a waterproof and dustproof push switch and, more particularly, to a waterproof and dustproof push switch which can be easily assembled.
2. Prior Art
A conventional push switch has been disclosed, for example, in Japanese Utility Model Laid-Open No. 63-82327.
The conventional push switch according to Japanese Utility Model No. 63-82327 generally includes a body made of an insulating material having a fastening front plate and a hollow portion disposed in the central region thereof so that a shaft is inserted, through an end portion of the body, into the hollow portion. A first fixed contact member inserted and fastened to either of a pair of contact-member insertion holes is formed outside the hollow portion. A second fixed contact member is inserted and fastened to another contact-member insertion hole through another end portion of the body. A step-provided push shaft is inserted into the hollow portion so as to be supplied with a constant projecting elastic force toward the body by an elastic member. A movable contact member is secured to an end portion of the push shaft, inserted into the pair of contact-member insertion holes from an end portion of the body and arranged to have a pair of conductive elastic members so as to come in contact with the first fixed contact member and the second fixed contact member.
However, in the above-described conventional structure, a square projection at the end portion of the push shaft must be inserted into a square hole formed in the contact member when the movable contact member is fastened to the end portion of the push shaft. Therefore, assembly of the switch is not efficient since position-aligning and screw tightening tasks must be conducted.
Furthermore, when the push shaft is pushed, the movable contact member fastened to the end portion of the push shaft is forcibly moved outside the hollow portion of the body. Therefore, an insulating cover (which prevents contact with surround support structure to which the push switch is fastened becomes necessary. As a result, the number of the necessary components cannot be reduced, causing the overall cost to be raised undesirably.
In particular, since the above-described conventional structure has been arranged in such a manner that the waterproof cover is fastened to the body simply by fitting the groove of the waterproof cover to the flange of the body, the portion of the waterproof cover, other than the portion which is turned over at the time of mounting the body of the push switch on the vehicle body, can be easily separated. Therefore, a problem arises in that the working efficiency deteriorates critically.
Furthermore, it is necessary for the elastic member to be fastened to the push shaft prior to the fastening of the movable contact member to the push shaft. In addition, the movable contact member must be fastened to the push shaft against the urging force of the elastic member. Therefore, problems arise in that efficiency during assembly has been unsatisfactory. In addition, the assembly task itself has been dangerous since the elastic member can forcibly be ejected towards the worker.